JP2006044853A - Conveyor belt elongation measuring method and conveyor belt elongation measuring device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a conveyor belt elongation measuring method and a measuring device used for the same, capable of detecting magnetic marks formed on a conveyor belt with high reliability, and applicable also to a conveyor belt having an organic fiber cord as a tension member. <P>SOLUTION: Rubber magnets are embedded inside the conveyor belt, or sheet-like rubber magnets are stuck to the surface of the conveyor belt to form the magnetic marks on the conveyor belts. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for measuring the elongation of a running conveyor belt and a measuring device therefor.

  Large conveyor belts are often used at sites that are not maintained close to humans, such as mining sites for natural resources, and maintenance and inspection are not sufficiently performed. In such a field, for example, the conveyor belt may suddenly be cut and the operation may be interrupted. In this case, the restoration takes a lot of time and money, and thus preventive maintenance is required. There is a strong demand for a means of detecting a sign of an accident in advance so that it can be performed. As one of countermeasures, a method has been proposed in which if the conveyor belt stretch exceeds a predetermined size, the conveyor belt stretch is measured so that it can be judged as abnormal and can be inspected and repaired. (For example, refer to Patent Document 1).

  This known conveyor belt elongation measuring method is a method of magnetizing steel cords serving as tension members of a conveyor belt at two positions spaced apart in the length direction of the conveyor belt, and using these as magnetic marks. Each magnetic mark is detected by two magnetic sensors arranged in the length direction of the conveyor belt at a position away from the conveyor belt, and the conveyor belt is based on the difference in timing when these magnetic marks are closest to the magnetic sensor. This method is based on magnetic sensing, so it is not easily affected by the environment due to wind, rain, light, etc. outdoors, but a steel cord, which is a soft magnetic material, is worn. Since the magnetic mark is magnetized, it has a weak magnetic force, and the magnetic mark is affected by the external magnetic field. There is a problem that the reliability is not sufficient because it disappears or a magnetic mark is formed at another position.

As a matter of course, this method also has a problem that it cannot be used for a conveyor belt having an organic fiber cord as a tension member.
JP 57-48521

  The present invention has been made in view of such problems, and can detect a magnetic mark formed on a conveyor belt with high reliability. Moreover, the present invention provides a conveyor belt having an organic fiber cord as a tension member. It is an object of the present invention to provide a method for measuring the elongation of a conveyor belt and a measuring device used therefor.

In the invention <1>, each of the pair of magnetic marks formed on the traveling conveyor belt and spaced apart from each other in the length direction of the conveyor belt is arranged at a position away from the conveyor belt in the length direction of the conveyor belt. In the conveyor belt elongation measuring method for detecting the elongation of the conveyor belt based on the difference in timing when these magnetic marks are closest to the magnetic sensor, detected by the two magnetic sensors arranged,
This is a conveyor belt elongation measuring method in which a rubber magnet is embedded in a conveyor belt or a sheet-like rubber magnet is attached to the surface of the conveyor belt to form the magnetic mark on the conveyor belt.

  <2> The invention according to <2>, wherein, in <1>, as a magnetic sensor for detecting a timing at which the magnetic mark is closest, a loop coil type in which a loop conveyor length direction dimension is smaller than a rubber belt conveyor belt length direction dimension A sensor is used to measure the current generated in the coil due to the change in the magnetic flux lines in the loop coil accompanying the displacement of the magnetic mark during conveyor belt travel, and the reapproach timing of the magnetic mark is obtained from the waveform of this current change. It is a conveyor belt elongation measuring method.

In the invention <3>, in <1> or <2>, the magnetic mark is detected by two magnetic sensors arranged along the length of the conveyor belt, and one of these magnetic sensors is respectively the difference between the timing of detecting the closest of the magnetic mark and t _1, the two of the difference in timing of detecting the closest of each same magnetic marks in the magnetic sensor as t _2, the conveyor based on the formula (1) The method for measuring the elongation of a conveyor belt according to claim 1 or 2, wherein the elongation ε of the belt is obtained.

ε = ((L _a xt ₁ / t ₂ −L ₀ ) / L ₀ ) × 100 (%) (1)
However,
L _a : Separation distance measured along the conveyor belt length direction of two magnetic sensors L ₀ : Separation measured along the conveyor belt length direction of both magnetic marks in a state where the elongation of the conveyor belt is zero distance

The invention <4> is an elongation measuring device used in the conveyor belt elongation measuring method according to any one of <1> to <3>.
A pair of rubber magnets that are embedded or affixed at positions separated from each other along the length direction of the conveyor belt to form each of the magnetic marks, and along the length of the conveyor belt at a position away from the conveyor belt And a pair of magnetic sensors that detect the magnetic marks and are fixed at a predetermined distance from each other.

  <5> The invention according to <4>, wherein the width direction guide for regulating the width direction position of the conveyor belt is provided at a position away from the magnetic sensor on both sides in the width direction of the conveyor belt. It is an elongation measuring device.

  <6> The invention according to <4> or <5>, wherein the pair of rubber magnets are arranged one by one on both sides of a joint portion extending in the conveyor belt width direction of the reinforcing material constituting the conveyor belt. This is a conveyor belt elongation measuring device.

  According to the invention of <1>, a hard magnet is used because a rubber magnet embedded in the conveyor belt or attached to the surface thereof is used instead of a magnetic mark magnetized with a steel cord. A rubber magnet with a large coercive force is less affected by the surrounding magnetic field, can improve the reliability of detection by a magnetic sensor, and is also applicable to a conveyor belt whose tension member is an organic fiber cord. Elongation can be measured.

  Rubber magnets are made of rubber as a matrix with magnet powder dispersed therein, and have great flexibility, even if embedded in a conveyor belt that is used while being bent or deformed. It can be deformed following the deformation of the bare belt, and high durability can be obtained.

  According to the invention <2>, a loop coil type sensor is used as a magnetic sensor for detecting the timing at which the magnetic mark is closest, and a change in the magnetic flux lines in the loop coil accompanying the displacement of the magnetic mark during conveyor belt travel The current flowing through the coil is measured in proportion to the current change, and the reapproach timing of the magnetic mark is obtained from the waveform of this current change. Therefore, even if the conveyor belt meanders and misalignment occurs, the magnetic mark is detected. Measurement reliability can be increased. In addition, since the length of the loop in the conveyor length direction is set to be smaller than the length of the rubber magnet in the conveyor belt length direction, the detection accuracy does not deteriorate due to the wide loop.

  According to the invention <3>, the magnetic mark is detected by two magnetic sensors arranged along the conveyor belt length direction, and the timing of the closest approach of the magnetic sensor is determined based on the formula (1). Since it detects, elongation can be measured with a very simple measuring device.

  According to the invention of <4>, the pair of rubber magnets embedded in or pasted at positions separated from each other along the length direction of the conveyor belt and forming each of the magnetic marks, and separated from the conveyor belt Since it is provided with a pair of magnetic sensors that are fixed to each other at predetermined intervals along the length of the conveyor belt and detect the magnetic marks, as described above, the apparatus is simple and high. Elongation can be measured reliably.

  According to the invention <5>, since the width direction guide for regulating the width direction position of the conveyor belt is provided at positions away from the magnetic sensor on both sides in the width direction of the conveyor belt, meandering and positional deviation in the width direction of the conveyor belt are provided. The measurement error due to can be eliminated, and the measurement can be performed with higher accuracy.

  According to the invention <6>, since one rubber magnet is provided on each side of the joint portion of the reinforcing material, which is most likely to cause belt cutting, belt cutting can be predicted with high probability.

An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a side view showing a conveyor belt stretch measuring device of the present embodiment, FIG. 2 is an enlarged cross-sectional view showing a portion A of FIG. 1, and FIG. It is a corresponding fragmentary sectional view. The conveyor belt elongation measuring apparatus 1 includes magnetic measurement stations 10A and 10B provided in a manner spaced apart from each other by _a predetermined interval La along the conveyor belt length direction, and the conveyor belt 11 in the conveyor belt length direction. It comprises a pair of rubber magnets 2 embedded at spaced positions. In the figure, reference numeral 12 denotes a pulley that drives or guides the conveyor belt 11.

  A pair of rubber magnets 2 form magnetic fields having magnetic lines of force indicated by M in FIG. 2, that is, magnetic marks, respectively, while magnetic measurement stations 10A and 10B are provided with magnetic sensors 3A and 3B, respectively, During traveling, the magnetic mark passing through the conveyor belt length direction is arranged to detect the closest approach timing. Each rubber magnet 2 may be embedded in the rubber part on either side of the front and back sides separated by the steel cord layer 11b serving as a reinforcing material for the conveyor belt 11.

  Here, the feature of the present invention is that a rubber magnet 2 embedded in the rubber portion of the conveyor belt is used as the magnetic mark, and this makes it possible to magnetize a part of the steel cord having a high magnetic permeability but a low coercive force. In contrast to the case where the magnetic mark is used, the measurement is less affected by the external magnetic field and enables stable and reliable measurement.

In the present embodiment, the rubber magnet is embedded in the rubber of the conveyor belt. Alternatively, the rubber magnet may be formed into a sheet and attached to the surface of the conveyor belt.

  The magnetic sensors 3A and 3B are attached to a base plate 17 elastically supported via a spring 16 on a support block 15a of a support column 15 fixed to the ground. The base plate 17 is lengthwise of the conveyor belt 11 by restraining means (not shown). However, it is provided in the width direction and the thickness direction so that it can be displaced by the expansion and contraction of the spring 16. In order to obtain high detection sensitivity, the magnetic sensors 3A and 3B are preferably provided as close as possible to the passing position of the rubber magnet 2 and close to the surface of the conveyor belt 11 on the side where the rubber magnet 2 is embedded. It is arranged on the vertical plane L.

  The position in the width direction of the conveyor belt 11 is regulated at a position away from the magnetic sensor 3 on both sides in the belt width direction, and the width direction position of the rubber magnet 2 embedded in the conveyor belt 11 with respect to the magnetic sensor 3 is constant. The width direction guide 9 is provided on the side plate 22 of the base plate 17 that supports the magnetic sensor 3, the spring 23 is attached to the support column 15, and is linear. The guide 27 includes a guide roller 19b guided by the linear guide 27 and provided on the base plate 17 so as to be displaceable in the width direction, and a spring 26 supported by the other side plate 24. Due to the action, the magnetic sensor 3 and the conveyor belt 11 are pressed against one end in the width direction of the conveyor belt 11. Holds the relative position, the guide roller 19b, by the action of the spring 26, pressed to the other widthwise end of the conveyor belt 11, it serves to prevent the conveyor belt 11, the spacing from the guide roller 19a.

  Further, a thickness direction guide roller 9 a is attached to the base plate 17, and the guide roller 9 a is pressed against the inner surface in the thickness direction of the conveyor belt 11 by the action of the spring 16. It is possible to keep the separation distance from the constant.

  The guide rollers 19a, 19b, and 9a were used instead of a flat plate for the restriction of both the width direction and the thickness direction of the conveyor belt, but if a flat plate is used, this is due to friction with the flat plate. This is to prevent the conveyor belt 11 from being worn and the relative position to the magnetic sensor 3 from changing.

In addition to the magnetic sensor 3A, the magnetic measurement station 10A also includes a width direction guide 9, a base plate 17, a side plate 22, guide rollers 19a, 19b, 9a, a support column 15, springs 16, 23, 26, and a linear guide 27. Similarly, the magnetic measurement station 10B includes the above-described components in addition to the magnetic sensor 3B. The separation distance between the magnetic sensors 3A and 3B is set to be the same as the separation distance between the magnetic measurement stations 10A and 10B.

  FIG. 4 is a block diagram showing a control part of the conveyor belt elongation measuring device 1. The conveyor belt elongation measuring device 1 inputs measured values from both magnetic sensors 3A and 3B, and conveys from the inputted values. The field control device 5 that calculates the elongation of the belt 11 and transmits the calculation result by radio waves, receives the calculation result from the field control device 5, and outputs the calculation result to the output terminal 7 or the elongation is predetermined. And a central controller 6 that issues an alarm when a threshold value is exceeded.

  In the above description, the calculation means for obtaining the elongation of the conveyor belt 11 is arranged in the field control device 5, but this can also be provided in the central control device 6. In this case, the field control device 5 is provided with the magnetic sensor 3A. 3B functions as a transmitter that only transmits data from 3B to the central controller 6.

A method for obtaining the elongation of the conveyor belt 11 by using the conveyor belt elongation measuring apparatus 1 configured as described above will be described. The principle of this elongation measuring method is as follows. The distance measured along the length of the conveyor belt between the pair of rubber magnets 2 embedded in the conveyor belt 11 when no stress is applied to the conveyor belt 11 and the elongation is zero is L ₀ , the conveyor belt 11. When the distance between the rubber magnets 2 in the state where the elongation occurs is L _x , the elongation ε can be generally expressed by Equation (2).

ε = (L _x −L ₀ ) / L ₀ x100 (%) (2)

The magnetic sensor 3A, 3B one, for example, a magnetic sensor 3A is a difference in timing of detecting the magnetic marks formed by both the respective rubber magnet 2 and t _1, the running speed of the conveyor belts 11 and V Then, the separation distance L _x in the equation (2) can be expressed by the equation (3).

L _x = t ₁ xV (3)

On the other hand, one of the magnetic marks in a pair, for example, the magnetic mark of the conveyor belt moving direction tip end side, the magnetic sensor 3A, the difference in timing of each 3B detects a t _2, these magnetic sensors when the distance of the cross was L _a, the travel speed V in the equation (3) can be represented by the formula (4).

V = L _a / t ₂ (4)

From the above formulas (2), (3) and (4), the above formula (1) can be easily derived. In this formula (1), the timing differences t ₁ and t ₂ are used as variables. From this, it is a simple configuration that combines the pair of rubber magnets 2 and the pair of magnetic sensors 3A, 3B that detect magnetic marks by the rubber magnets 2 as described above. The elongation of the conveyor belt 11 can be measured.

The elongation measuring method of the present invention using the above principle will be described more specifically with reference to FIG. FIG. 5A is a graph showing the change in magnetic flux density detected by one magnetic sensor 3A on the horizontal axis, and FIG. 5B is the magnetic flux detected by the other magnetic sensor 3B in the same manner. It is a graph which shows the change of a density. These magnetic sensors 3A, 3B is the peak portion of the magnetic flux density detected rubber magnets 2 magnetic marks 13a formed by, equivalent to 13b, the field control device 5, the magnetic flux density exceeds a certain threshold value H ₀ If detected, the magnetic marks 13a and 13b are determined to be processed.

The field control device 5 measures the difference t _{1 in} detection timing between the magnetic mark 13a on the front end side in the conveyor belt traveling direction detected by the magnetic sensor 3A and the magnetic mark 13b on the rear end side, and also detects the magnetic sensor 3A. And 3B measure the timing difference t _{2 at} which the magnetic mark 13a on the tip side is detected, and use these measured values t ₁ and t ₂ and preset values L _a and L ₀ to obtain an equation The elongation ε is calculated based on (1).

Also, by the distance L _a and L ₀ is previously set to be in advance the same, the formula (1) may be rewritten as Equation (5), as it is apparent from the equation (5), without using the value of L _a and L ₀ can be determined elongation Konberuto.

ε = (t ₁ / t ₂ −1) × 100 (%) (5)

  Here, by arranging two rubber magnets 2 together in the belt length direction, for example, at an interval of 100 m, the belt elongation at each position can be measured over the entire length of the belt. In addition, the joint portion extending in the width direction of the steel cord 11b serving as a reinforcing material for the conveyor belt 11 is a portion that supports the strength in the length direction only by adhesion of rubber, and is likely to increase in elongation. The rubber magnets 2 are preferably arranged one by one on both sides of the joint.

  The rubber magnet 2 is preferably a matrix composed of at least one rubber component selected from the group consisting of butyl rubber and silicon rubber, and magnetic anisotropic magnetic powder dispersed in the matrix, such as a rare earth alloy. It consists of magnetic substance powder which consists of.

  By using the specific rubber component as the matrix of the rubber magnet 2, it is not broken or broken even when subjected to intermittent bending stress or tensile stress, and stabilizes the magnetic force over a long period of time. be able to.

When butyl rubber is used as the rubber component of the rubber magnet 2, the butyl rubber preferably has an unsaturation degree of 0.3% or less and a Mooney viscosity ML _{1 + 4} (100 ° C.) of 60 or less. When the degree of unsaturation of butyl rubber is less than 0.3%, a sufficient crosslinking point cannot be secured. On the other hand, when the Mooney viscosity ML _{1 + 4} (100 ° C.) of butyl rubber exceeds 60, the flexibility is too low, and the workability when kneading with magnetic powder is deteriorated. The butyl rubber may include halogenated butyl rubber, and examples of the halogenated butyl rubber include brominated butyl rubber and chlorinated butyl rubber.

  When silicon rubber is used as the rubber component of the rubber magnet 2, the silicon rubber has a low viscosity when kneaded at room temperature or in a heated state, and becomes high strength after curing. Liquid type RTV and the like are preferable. Here, the room temperature curable RTV is silicon rubber commercially available from Shin-Etsu Chemical Co., Ltd.

The magnetic powder used for the rubber magnet 2 can be the same as the magnetic powder used for the conventional hard composite sheet. Specifically, magnetic anisotropic magnetic powder such as rare earth magnetic powder is used. Good. Here, examples of the rare earth magnetic material include NdFeB and SmFeN.
It is.

  Although a Hall element can be used as a magnetic sensor, a loop coil type sensor is used, and a current generated in proportion to a change in the number of magnetic lines passing through the loop in response to the approach of the magnetic mark is generated. By measuring, it is possible to determine the closest position of the magnetic mark. According to this method, the magnetic mark can be reliably detected even if the conveyor belt is meandering or misaligned. It is preferable in that it can be increased. Here, the length of the conveyor belt in the length direction of the loop is preferably smaller than the length of the rubber magnet 2 in the conveyor length direction. If the length of the loop in the conveyor belt length direction is too large, the detection accuracy is deteriorated. Further, the size of the loop in the width direction of the conveyor belt may be sized so as to cover the misalignment according to the degree of misalignment of the conveyor belt, for example, about 10% of the width of the conveyor belt. it can.

As explained above, according to this conveyor belt stretch measurement method, the stretch of the conveyor belt can be measured simply by using the two magnetic sensors 3A, 3B and the rubber magnet 2, Since the measurement is a non-contact type based on magnetic measurement, it is possible to provide a highly reliable method that is not affected by the waviness or pulsation of the belt.

It is a side view which shows the conveyor belt elongation measuring apparatus of embodiment which concerns on this invention. It is sectional drawing which expands and shows the A section of FIG. It is a fragmentary sectional view corresponding to the BB arrow of FIG. It is a block diagram which shows the control part of a conveyor belt elongation measuring apparatus. It is a graph showing the time change of the magnetic force detected with the magnetic sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conveyor belt elongation measuring device 2 Rubber magnet 3A, 3B Magnetic sensor 5 Field control device 6 Central control device 7 Output terminal 9 Width direction guide 9a Thickness direction guide 11 Conveyor belt 11b Steel cord layer 13 Magnetic mark 12 Pulley 15 Support column 15a Support Block 16 Spring 17 Base plate 19a, 19b Guide roller 22 Side plate 23 Spring 24 Side plate 26 Spring 27 Linear guide

Claims (6)

A pair of magnetic marks formed on a traveling conveyor belt and arranged at intervals in the length direction of the conveyor belt are arranged in the length direction of the conveyor belt at two positions apart from the conveyor belt. In the conveyor belt elongation measurement method for detecting the elongation of the conveyor belt based on the difference in timing detected by the sensor and when these magnetic marks are closest to the magnetic sensor,
A conveyor belt stretch measurement method in which a rubber magnet is embedded in a conveyor belt, or a sheet-like rubber magnet is attached to the surface of the conveyor belt to form the magnetic mark on the conveyor belt.   As a magnetic sensor for detecting the timing at which the magnetic mark is closest, a loop coil type sensor in which the loop conveyor length direction dimension is smaller than the rubber magnet conveyor belt length direction dimension is used. The conveyor belt elongation measuring method according to claim 1, wherein a current generated in the coil due to a change in a magnetic flux line in the loop coil accompanying the displacement is measured, and a reapproach timing of the magnetic mark is obtained from a waveform of the current change. The magnetic mark is detected by two magnetic sensors arranged along the length of the conveyor belt, and the difference in timing when one of these magnetic sensors detects the closest approach of each magnetic mark is t _1. , the difference between the timing at which each of the two magnetic sensors detects the closest of the same magnetic marks as t _2, the conveyor belt according to claim 1 or 2 Request elongation ε of the conveyor belt on the basis of the equation (1) Elongation measurement method.

ε = ((L _a xt ₁ / t ₂ −L ₀ ) / L ₀ ) × 100 (%) (1)
However,
L _a : Separation distance measured along the conveyor belt length direction of two magnetic sensors L ₀ : Separation measured along the conveyor belt length direction of both magnetic marks in a state where the elongation of the conveyor belt is zero distance
An elongation measuring device used in the method for measuring the elongation of a conveyor belt according to any one of claims 1 to 3,
A pair of rubber magnets that are embedded or affixed at positions separated from each other along the length direction of the conveyor belt to form each of the magnetic marks, and along the length of the conveyor belt at a position away from the conveyor belt A conveyor belt elongation measuring device comprising a pair of magnetic sensors which are fixed to each other at a predetermined interval and detect the magnetic mark.   The conveyor belt elongation measuring device according to claim 4, wherein a width direction guide for regulating the width direction position of the conveyor belt is provided at a position away from both sides of the magnetic sensor in the width direction of the conveyor belt. The conveyor belt elongation measuring device according to claim 4 or 5, wherein the pair of rubber magnets are arranged one by one on both sides of a joint portion of the reinforcing member constituting the conveyor belt extending in the conveyor belt width direction.

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